This invention relates to packets, particularly but not exclusively to infusion packets containing an infusible material, such as tea bags, especially of the type having an attached string and tag or envelope, and to packaging methods of producing such packets.
Tea bags consist of doses of dried and shredded tea leaves sealed in compartments made of a readily permeable web material, generally referred to as paper although it may have a significant plastics content. The bags may be formed from folded-over tubular lengths of the paper so that each bag has a pair of compartments containing the infusible material one on each side of the fold.
Examples of such twin-compartment bags can be found in GB-A-681816, GB-A-870800, US-A-2593608 and US-A-2925171. These documents also show bags in which a tubular length of the paper is given a W-shaped fold across the middle of its length. As a result of the fold, the two open ends of the tubular length are brought together, and can then receive their doses of tea or other infusible material from twin nozzles inserted then into the open ends to fill both tubular compartments simultaneously, as shown in GB-A-870800. The open ends are typically folded over and closed by being stapled or clipped or heat-sealed together. A tag may be attached to the staple by means of a thread, to make it more convenient for the consumer to handle the bag in use.
It is also known to make tea bags of this twin-compartment form in which the bag has been sealed at the W-fold to close off the compartments from each other.